Unscrewing attachment for drill pipe



April'8, 1930. A. E. MARTols ET AL 1,753,244

UNSCREWING ATTACHMENT FOR DRILL PIPE Filed Feb. 16, 1929 j INVENTOR.

ATTORNEY.

Patented Apr. 8, 1930 UNITED l STA TES PATENT or-Ficn ARTHUR E. MARTOIS, OF COMPTON, AND ROBERT D. PEARSON, OF LOS ANGELES, f

- CALIFORNIA UNscnEWING ATTACHMENT Fon DRILL PIPE v Application led February 16, 1929. Serial No. 340,624.

This invention relates to an apparatus for more e'iciently applying power to a drill pipe for the purposevof screwing together or unyscrewing the joints thereof.

An object ofthe invention is to provide im'- proved means whereby the power is applied to such joints with a greater leverage atl the beginning of the unscrewingmovementto loosen a joint,'and with a less leverage but greater speed afterthejoint has been .turned suiiciently to loosen the same. Y A further object of the invention is to provide an improved gripping device which will very effectively grapple the parts to be screwed or unscrewed and which will automatically fasten itself securely to such part in whichever direction it is rotated.

Other objects and advantages may hereinafter appear. n n

Referring to the accompanying drawings which illustrate a preferred embodiment of the invention, v v

Fig. 1 is a transverse section on line 1-1 of Fig. 5,'one position of the device being indicated by dotted lines. v

Fig. 2 is a vertical section on line2-2 of Fig. 1, showing also a fragment of the drill pipe line to which the device is being applied.

Fig. 3 is an enlarged transverse section of the gripping slips shown in the central portion of Fig.

Fig. 4 is a side elevation ping slips.

Fig. 5 is a side elevation of the parts shown in Fig. 1.

Referring in detail to the drawings, the housing comprises a mainsection 9 and the gate portion 10, said gate portion being pivotally secured to the body portion 9 by Ameans of a pivot pin or bolt 11. As well shown in Fig. 5, said gate portion 10 is composed of an upper part 12 and a lower part 13 said parts being secured together by the tie bolts 14. When said gate 10 is swung to its closed position its free end may be secured to the body portion of the housing by means of a fastening pin 15.y

The body portion of the housing is provided on each of its opposed inner faces with a semi-circular groove 2O to receive asemiof one of the` gripi circular rib 21 which projects from the halfgear 22, it being understood that the gate portion 10 is to be provided with a like groove, and the complementary half-gear 25 is also provided with a rib to seat slidably in the last mentioned groove so that when the complementary gear parts are in their oper-V ative position, a complete rotative gear will be housed within the device.

The complete gear which has been described is of an annular form andencircles la plurality of circumferentially Varranged spaced gripping slips 30 which, in turn, surround the drill pipe line 31 vand which are provided on their inner surfaces with teeth 32 adapted to grip the joint of said drill pipe line which is to be screwed into place, or unscrewed from the tool pipeline when the device is operated.

, Said slips 30 are tapered longitudinally as shown to cause them to drop into a position for firm gripping. vSaid gripping slips 30 are thicker at their mid-widths than at their sides, their exterior faces 30f meeting at an obtuse angle 30a in order to adapt them to rock transversely and thus perform their gripping function in whichever directionthe device is rotated.V The reduced end portions of these slips are tted into place as shown in Fig. 2. Spaces 30b between slips 30 provide yroom for their operation. n

Between the gripping slips'30 and the annulargear sections 22 and 25 are interposedV a plurality of dogs 35vrpivoted at their midlengths'on pins36 so as to swing in a plane at right angles to the axis of thetool line.

Saiddogs are normally held in their operative positionby springs 35s coiled around their pivots.

Retaining rings 35r and 33r are provided to retain the dogs 35 in their operative positions. The ring 351" is recessed as shown, in order to provide room for the dog springs 35S. There is provided for the upper end of the device, when viewed in the operative position, a'retaining and bearing cap 37 having an internally projecting attaching flange 38 whereby it holds slips 30 in position as shown in Fig. 2. It is in two parts like the gears. Said cap 37 has a peripheral stop flange 37 s.

The body portion 9 of the housing is of an elongated form and is provided with an internal guide passage 4() which extends from 'end to end thereof. V'Vithin said guide passage 40 is slidably mounted a rack bar 41 having a toothed portion 42 which operatively engages the teeth of the gear formed by the gear halves 22 and 25. The outer end of.

said rack bar 41 is provided with a.' head 43 having an attaching handle or stirrup 44, whereby it may be secured to any suitable operating device, not shown.

As viewed in Fig. 1, the lett end of the rack bar 41 is provided with a stop element. desirably a plate or clip 45 which is a -tached thereto by a screw 46 and which abuts against the left end of" the housing body 9 when the rack is fully extended as indicated in dotted lines in this view.

The body portion of the housing 9 is provided wth a semi-circular extension or tapering flange 9X, and the lower part 13 of the gate l0 is provided with a like extension or flange 13x adapted to complement said extension 9X andthus form, when the gate is closed, a sleeve-like extension having therewithin an inwardly tapering recess 9Y of suficient depth still to encircle the upper end ot the tool pipe line after a joint has been unscrewed therefrom. This construction, well shown in Fig. 2, prevents the tool pipe line from toppling over from one side to theA other K immediately after a joint has been removed from its upper end.

In assembling the parts, while the gate 10 is open and the rack bar in the position shown Vin full lines in Fig. 1, the half-gear 22 is placed in the position shown in this view, then half the slips 32 are inserted. Then the corresponding gear half 25 and remaining half of the slips are put in place within the gate, after which the gate may be swung to its closed position around the tool vline as shown in Fig. 1. Before the rotatable parts can conveniently be removed they must also be brought back to the position shown in Fig. 1 wherein one half-gear is contained within the gate of the housing and the other halfgear is contained within the body portion of the housing.

In operation, assuming the parts to be in the positions shown in full lines in Fig. 1,

. wherein the gate lOhas been swung to its closed position and fastened in that position by means of the latch pin 15, power will be applied trom the engine in such a manner as to producetraction upon the stirrup 44 in the direction indicatedby the arrow in the upper right hand portion of this view. The

first effect of this traction will be to produce a powerful rotary movement of the device causing it more firmly to grip the tool pipe line and thereby loosen toward an unscrewed position the particular tool joint to which it is applied, then farther traction upon the device will move the rack bar 41 longitudinally toward the position shown in dotted lines in Fig. 1. It will be seen that in this manner a powerful leverage Vis secured for the vinitial rotary movement to loosen the part to be unscrewed, the leverage being lessened but' the speed of movement increased during the latter part of operation.

Claims:

1. A drill pipe wrench comprising a twopart housing, adapted Jfor mounting upon a rotatable pipe, or coupling, gripping means, and means for rotating the latter; each part ot said housing having a substantial eXtension projecting axially beyond the zone of action of t-he gripping means and formed to enclose 'and maintain a section of the pipe not gripped by the gripping means in line with the portion or coupling so gripped.

2. A pipe wrench comprising a housing adapted for mounting upon a rotatable pipe, or coupling, gripping means adapted to grip said pipe or coupling and comprising a gearwheel, a rack operatively engaging said gearwheel, and a hollow handle within which said rack is slidable, said handle forming an extension of said housing and said rack having a portion which projects beyond said housing and is at all times accessible for the purpose of attaching means thereto to impart a coipxbined traction and swinging torce to said rac v In testimony whereof we affix our signa- 

